Microwave dielectric properties and relaxation characteristics of Ba0.5Sr0.5TiO3 –Bi2MoO6 composite ceramics

Abstract

The (1-x) Ba0.5Sr0.5TiO3-xBi2MoO6 (x = 10, 20, 30, and 40 wt%) composite ceramics were successfully synthesized through a conventional solid-phase reaction method, and the influence of A- and B- site co-doping on the dielectric properties of the BST composite ceramics was comprehensively investigated. Bi3+ ions acted as donors to replace Ba2+ and Mo6+ replaced Ti4+, producing a (BiBa∙ + MoTi∙∙)-VBa″ dipole to achieve electrovalent equilibrium. In addition, the liquid phase inhibited the growth of grains and promoted densification of the composite ceramics. The degree of B-site order was analyzed using Raman spectroscopy. With an increase in the amount of Bi2MoO6 composite, the dielectric permittivity peak broadened, the Curie temperature gradually decreased, and the tunability of the composite ceramics declined gradually. The dielectric properties of the composite ceramics benefitted from the inclusion of Bi2MoO6 and its composite effects. At the composition of x = 30 wt%, the composite ceramics exhibited excellent comprehensive properties with ε = 457 (RT), T = 14% (at 30 kV/cm), and Q = 780 (at 1148 MHz).